More than 50 heron chicks in the park have been killed in the last 20 days, Stanley Park Ecology Society conservation programs officer Robyn Worcester said Thursday.

“We’ve actually seen evidence of raccoons eating part of them and leaving it there, and some volunteers actually witnessed a raccoon munching on one,” Worcester said. “It started a couple of weeks ago, and it’s getting worse.”

Worcester said it’s not uncommon for raccoons to go after herons, but the number of heron deaths she has seen this year is off the charts.

“There’s a really high population of raccoons in Stanley Park because people feed them, so we’re attributing it to the fact that the population of raccoons in Stanley Park has gotten higher,” she said.

“It’s just a theory, but maybe a certain family of raccoons has figured out, ‘Oh, we can eat these,’ so now they’re eating them every night.”

Raccoons are boreal animals, which means they live in trees, Worcester said. They often sleep in empty heron nests during the day.

“But now they have turned on the herons, and instead of being roommates, they are eating them,” Worcester said.

Worcester is hoping to install predator guards — metal shields around trees that make it too slippery for animals such as raccoons to climb — before next year’s nesting season. That would keep the raccoons out of the trees that house heron nests, located next to the public tennis courts in Stanley Park.

Despite the raccoon problem, the Stanley Park heron colony is very lively — and noisy — this time of year, with lots of chicks in the nests fighting for food.

“When the parents come to feed them, they fight and they squawk. It sounds horrible, but it’s normal,” Worcester said.

There are roughly 500 herons currently nesting in Stanley Park, Worcester estimated. In addition to raccoons, herons are sometimes targeted by eagles, and by their own brothers and sisters, in a process called siblicide.

“If there is lots of food, they all survive, but if there is not very much food, only the big chicks survive,” she said. “The little ones don’t starve, though. The big one actually pushes them out of the nest.”